I hashed my bag and in it I put… “Is there a hash for unordered items?”Can't one simply hash all items individually and then hash the sum of all hashes? And then, in order to prove a certain item's presence, provide its hash and that of the sum of all other hashes, and the sum of these two again hashes to revealed hash? On second thought, hashing the sum wouldn't do any good; why not simply sum all items' hashes?

I hashed my bag and in it I put… “Is there a hash for unordered items?”@cygnusv Hm, let me think about this... Commutativity would yield easy collisions, so the inner hash should be a "proper" one instead, right? But then again, if I understood it correctly those collisions are very peculiar and, given strings, would mostly yield garbage words. But still, sha512 for the items themselves wouldn't hurt...

What is the actual difference between security through obscurity and true encryption?Re "Everything should be made public", shouldn't that rather read "Everything becoming public should not compromise the actual encryption"? With that I mean for example a primitive rot-13-ing of an RSA encrypted message should not be considered safer than RSA alone, but it would at least keep script kiddies with a brute force cracker out for a while since they would have to find and use their brains first. And reducing the amount of potential attackers is not so bad, as is in some scenarios increasing the shortest possible attack duration